This invention relates to an image reading apparatus which is capable of synthesizing an original image previously read in with another image such as of characters and emitting the product of synthesis as an output.
Heretofore, a digital micro-reader printer (DMP) has been known as an image reading apparatus for reading such original documents as image frames photographed as in a microfilm. The reader printers of this class produce images on a screen or printed images on a paper for reading or viewing by a procedure which comprises projecting a beam of light from a light source through a condenser lens on the image of a selected one of the original documents serially photographed in a microfilm loaded on a microfilm carrier, subjecting to adjustment of focus and adjustment of magnification the beam of light which has passed through the microfilm by means of a projecting lens, and projecting the consequently adjusted beam of light on a screen or converting the beam of light into an electric signal by means of a line sensor and supplying the electric signal as to a laser beam printer.
Among the reader printers of this class is counted a reader printer which is endowed with a function of synthesizing an image read out of a microfilm (microimage) with another image as of characters and figures of date and time introduced from a personal computer and printing out the product of synthesis. FIG. 13A, for example, shows a microimage which is projected on a screen 11. The symbols "p" and "q" used in the diagram stand respectively for an area of the microimage on the screen 11 and an area other than that. FIG. 13B shows an image which is obtained when the microimage is read out by a line sensor such as the CCD, processed as normally required, and printed out on a sheet M. FIG. 13C depicts a case of synthesizing the image shown in FIG. 13B with a row of characters introduced as from a personal computer and printing out the product of synthesis.
Since the conventional image reading apparatus of this kind has the sole function of simply synthesizing a microimage read out of a microfilm with another image such as of a row of characters, however, it is at a disadvantage in incurring the possibility of the image area of the microimage overlapping the row of characters, depending on the size of the microimage to be read out, the margin of the microimage, the position of the microfilm to be read out, and the size of the row of characters (length, number of lines, etc.) to be synthesized, and the produced image betraying a missing part (refer to FIG. 13C).
Heretofore, for the sake of precluding the occurrence of such a missing part in the output image, it has been customary to adopt a method which comprises causing the operator of the apparatus to adjust manually the position of the microfilm or to alter manually the ratio of magnification of projection of the microfilm so that the non-image area of the microimage may fit in the area assigned for the insertion of the row of characters during the course of synthesis, for example. These methods, however, prove inconvenient for the operator because the position of the microfilm or the ratio of magnification must be readjusted each time the size of the row of characters being used in the synthesis is changed or the ratio of photographing the microfilm is changed.